Abstract: The present invention provides a process for the recovery of radiolabelled isotopes from organic substances labelled or contaminated with one or more radiolabelled isotopes, which process comprises: i) adding organic substances labelled or contaminated with a radiolabelled isotope to an acidic aqueous electrolyte containing silver ions as an electrochemically regenerable primary oxidising species; ii) subjecting the acidic aqueous electrolyte to an electric potential; and iii) recovering the radiolabelled isotope from the products of the electrochemical process resulting from the application of the electric potential; wherein the process is carried out at a slight pressure depression.

Abstract: Metal objects are treated by anodising the metal object in contact with an acidic solution, and then subjecting the anodised metal object to a reversed voltage (compared to the anodising voltage). The thus-treated metal object is then contacted with a biocidal metal-containing solution. Biocidal metal is deposited on the surface of the metal object, resulting in improved biocidal properties.

Abstract: An implant with a metal structure for use in a surgical procedure, in which at least part of the metal structure is coated with a biocompatible metal such as titanium by plasma spraying of the metal powder. Biocidal metal cations are then absorbed by ion exchange into the coating, so that after being implanted the biocidal ions gradually leach out into the surrounding body fluids and suppress infection. The ion exchange properties of the coating may be modified by pretreatment with dilute phosphoric acid.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodizing, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodising, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodising, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: An implant with a metal structure for use in a surgical procedure, in which at a region of the implant to be in contact with bone the metal structure is provided with a roughened surface. The roughened region is then provided with a ceramic coating comprising hydroxyapatite by a thermal spraying process. Biocidal ions of silver are absorbed into the ceramic coating, and gradually leach out into body fluids after implantation. The hydroxyapatite enhances bone regrowth into the implant, while the silver ions suppress infection.

Abstract: Using a solution mining procedure, an ore (10) is treated with a solution of acetic acid and hydrogen peroxide so as to form a leachate containing lead ions. Lead ions (and other metal ions such as zinc and manganese) are stripped (22, 24, 26) by solvent extraction from the leachate to form separate aqueous solutions. The aqueous solution containing lead ions is treated electrochemically in the anodic compartment of a separated electrochemical cell (42) to form a precipitate of lead oxide. Manganese dioxide can be produced similarly (72). A precipitate of zinc hydroxide can be formed in the cathode compartment of a separated electrochemical cell (56). In the cells (42, 72) extracting lead ions and manganese ions, the cathode compartment is used to generate hydrogen peroxide (for use in making the leachant), either directly or indirectly.

Abstract: In apparatus for decomposing organic waste by oxidation using electrochemically regenerated Ag++, provision is made for preventing unwanted carryover of organic material into recovery streams and into any solid waste produced by the apparatus. Gases formed in the processing are also treated to prevent or minimise any carryover of toxic components in gaseous effluent from the apparatus.

Abstract: A sensor for detecting chemical properties of a liquid, for example in an oil well, includes a glass pH electrode (22a) and a reference electrode (22c). The glass electrode (22a) consists of a narrow sensor electrode (30) on the surface of an electrically insulating substrate (20), a layer of glass (36) covering the sensor electrode (30), and two cleaning electrodes (32, 33) one extending along each side of the sensor electrode along its entire sensing length. The cleaning electrodes (32, 33) are not covered by the layer of glass, and are no more than 3 mm apart from each other. Application of a voltage between them generates gas bubbles by electrolysis that dislodge any fouling from the glass electrode (22a). The sensor electrode (30) may be of zigzag form, with the cleaning electrodes (32,33) interdigitated between the successive parts of the zigzag. A hydrophilic membrane (24) of sulphonated microporous PVdF provides further protection against fouling of the electrodes (22) by oil.

Abstract: Using a solution mining procedure, an ore (10) is treated with a solution of acetic acid and hydrogen peroxide so as to form a leachate containing lead ions. Lead ions (and other metal ions such as zinc and manganese) are stripped (22, 24, 26) by solvent extraction from the leachate to form separate aqueous solutions. The aqueous solution containing lead ions is treated electrochemically in the anodic compartment of a separated electrochemical cell (42) to form a precipitate of lead oxide. Manganese dioxide can be produced similarly (72). A precipitate of zinc hydroxide can be formed in the cathode compartment of a separated electrochemical cell (56). In the cells (42, 72) extracting lead ions and manganese ions, the cathode compartment is used to generate hydrogen peroxide (for use in making the leachant), either directly or indirectly.

Abstract: During filtration, periodic application of a potential difference between an electrically conducting filter medium and counter electrode (as anode) generates a gaseous product at the filter and cleans the filter. To minimise corrosion the counter electrode is of low chromium stainless steel, for example 9% chromium.

Abstract: An electrode for use in electrochemical ion exchange which includes a hydrolysable metal phosphate such as zirconium phosphate (Zr(HPO.sub.4).sub.2) which has been hydrolysed at least in part is regenerated. The electrode is made the anode of an electrochemical cell in which the electrolyte is an aqueous solution containing one or more phosphate ions provided, for example, by a dissolved salt (eg Na.sub.3 PO.sub.4, Na.sub.2 HPO.sub.4 or NaH.sub.2 PO.sub.4) or orthophosphoric acid, or both. Preferably, the electrolyte is acidic (eg pH 2). Operation of the cell reverses the hydrolysis reaction and enhances the performance of the electrode.